JPH06249957A - Area sensor - Google Patents

Abstract

PURPOSE:To provide an area sensor for detecting an obstacle or a person intruded into a plane by performing sector scanning using a light beam emitted from a light source. CONSTITUTION:The area sensor comprises a light source 1 for projecting a light beam, a light beam scanning means for shifting the light beam within a sectoral plane using a scanning reflector 2, a stripe means 3A disposed on a opposing face of the scanning means within the sectoral plane remote from the scanning means in order to reflect an incident light beam toward the scanning means, and a light receiving sensor 6 for capturing a light reflected on the reflecting means 3A and further reflected on the scanning reflector. The light source 1, the scanning means, and the light sensing means are provided integrally while corresponding with a light projecting/receiving section PR and other light projecting/receiving section having similar constitution and constitute an area sensor assembly integrally with a reflecting means RF. Intrusion into a tetragonal area can be detected using a pair of such area sensors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an area sensor for detecting an obstacle or an intruder that has entered a certain surface (area) for the purpose of danger prevention and crime prevention.

[0002]

2. Description of the Related Art In a well-known transmission type sensor, an obstacle is detected by detecting that light between a light source and a light receiving sensor is blocked by the obstacle. It is being appreciated. Therefore, the pair of light sources and the sensor can only capture the obstacle on the optical axis straight line. In order to catch an obstacle in a certain plane, it is necessary to prepare a large number of sensors and arrange them so that their optical axes are parallel to the plane. Further, it is necessary to secure the size (diameter) of the light receiving lens in order to obtain the required sensitivity for the distance between the optical axes, and it is difficult to set the distance to a certain degree (for example, 30 mm) or less. That is, the area sensor according to the conventional method may not be able to detect an intruding object (for example, a finger) within 30 mm. An object of the present invention is to solve the above-mentioned problem of detection accuracy by scanning in-plane with a novel structure,
An object is to provide an area sensor that can reliably detect an obstacle or an intruder that has entered a certain plane.

[0003]

In order to achieve the above-mentioned object, an area sensor according to the present invention comprises a light source for generating a light beam and a light-reflective surface for scanning the light beam in a fan-shaped plane. The light beam scanning means for emitting the light beam, the strip-shaped reflecting means arranged to face the scanning means in the fan-shaped plane away from the scanning means and reflecting the incident light beam to the scanning means, and the reflecting means. And a light sensing means for capturing and detecting light reflected by the scanning reflection surface and further reflected by the scanning reflection surface. The strip-shaped reflecting means may be a reflecting means having a regression characteristic. The light source, the scanning means, and the light sensing means are integrally provided to form a light emitting and receiving portion, and are provided integrally with the strip-shaped reflecting means corresponding to other light emitting and receiving portions having the same structure. A sensor assembly is formed, and the strip-shaped reflecting means and the other light emitting / receiving section corresponding to the light emitting / receiving section of the first assembly form a second area sensor assembly, and the first and second area sensors are formed. The assembly can form an area sensor that covers a generally rectangular area as a pair.

[0004]

The present invention will be described in more detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an area sensor according to the present invention. The light beam from the laser light source 1 is projected onto the movable mirror 2 through a hole provided in the central portion of a light receiving mirror 4 for receiving reflected light described later. The movable mirror 2 forms a light beam scanning unit that emits the light beam so that the light beam is moved in a fan-shaped plane by a reflecting surface for scanning. The mirror 2 is swung or rotated by a drive signal from the control unit 8. Similar results can be obtained by using a polygon mirror instead of the movable mirror 2. The light beam oscillated by the mirror 2 is arranged on the surface facing the scanning means in a fan-shaped plane and forms a strip-shaped reflecting means for reflecting the incident light beam to the scanning means (for example, from 3M). Reflected by 3A and reflected. It should be noted that any point on the surface of the strip-shaped reflective tape 3A has a regression characteristic (characteristic that reflects light in the direction of incident light).
The light incident on A is reflected in the direction of the movable mirror 2 for scanning described above. The light that reaches and is reflected by the scanning movable mirror 2 is further reflected by the above-mentioned light-receiving mirror 4 and condensed by the condenser lens 5 on the light-receiving sensor 6. When an obstacle enters between the center O of the movable scanning mirror 2 and the scanning range P → P ′ of the reflection tape 3A which is the reflection means, the laser beam is blocked by the obstacle and the amount of light reaching the light receiving sensor 6 is reached. Is decreased, the obstacle can be detected from the change in the output of the light receiving sensor 6. As a result, triangular POP '
Obstacles in the plane of can be detected.

As a practical problem, it is often required to detect intrusion into a rectangular area, so that the apparatus according to the present invention can cope with such an area by using two sets of area sensor assemblies. I am The area sensor assembly (UN) is composed of a light emitting / receiving unit (PR) and a reflecting unit (RF). As shown in FIG. 1, the light emitting / receiving unit (PR) is provided with a laser light source 1, a movable mirror of a scanning unit 2, a light receiving mirror 4, a condenser lens 5, and a light receiving sensor 6.
The light projecting / receiving unit (PR) is integrally provided with a reflecting unit (RF) including a reflecting tape 3B corresponding to another light projecting / receiving unit (PR).

FIG. 2 shows a pair of area sensor assemblies (UN1).
FIG. 6 is a layout diagram showing a usage example of rectangular area detection using (UN2). In the figure, (A) is a plan view, (B) is a front view, and (C) is a side view. Optical axis 1 and optical axis 2 indicate the axes of the light beams of the area sensor assemblies (UN1) and (UN2), respectively. As shown in FIG. 2C, the area of the triangular RUT is formed by the light emitting / receiving section (PR1) of the area sensor assembly (UN1) and the reflection section (RF2) of the area sensor assembly (UN2). The area of the triangular TSR is covered by the light emitting / receiving section (PR2) of (UN2) and the reflecting section (RF1) of the area sensor assembly (UN1) so that the intrusion into the area of the quadrilateral RUTS can be monitored as a whole. There is.

[0007]

As described above in detail, the area sensor according to the present invention can detect the intrusion of the fan-shaped area by using only the light source, the light beam scanning means, and the strip-shaped reflecting means. The intrusion into the quadrilateral region can be easily monitored by forming an area sensor assembly in which the light emitting / receiving unit and the strip-shaped reflecting means are integrally provided and using a pair of them. It should be noted that the area sensor assembly can be installed as it is because it can be used as it is while being housed in one long housing whose one surface is covered with a transparent plate. The blind spots in the detection area can be minimized by overlapping the boundaries of the paired area sensor assembly.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an area sensor according to the present invention.

FIG. 2 is a layout showing an example of use of the area sensor assembly according to the present invention.

[Explanation of symbols]

 1 Laser Light Source 2 Movable Mirrors 3A, 3B Reflective Tape 4 Receiving Mirror 5 Condensing Lens 6 Light Receiving Sensor 8 Control Circuit UN Area Sensor Assembly PR Emitter / Receiver RF Reflecting Means

Claims (3)

[Claims] 1. A light source for generating a light beam, a light beam scanning means for emitting the light beam so as to move in a fan-shaped plane by a reflecting surface for scanning, and a fan-shaped plane distant from the scanning means. A strip-shaped reflecting means for reflecting the incident light beam on the facing surface of the scanning means to the scanning means, and capturing light reflected by the reflecting means and further reflected by the reflecting surface for scanning. The area sensor is composed of the optical sensing means for detecting by. 2. The area sensor according to claim 1, wherein the strip-shaped reflecting means is a reflecting tape having a regression characteristic. 3. The light source, the scanning means, and the light sensing means are integrally provided to form a light emitting / receiving portion, and are provided integrally with a strip-shaped reflecting means corresponding to another light emitting / receiving portion having a similar structure. Forming a first area sensor assembly, the strip-shaped reflecting means corresponding to the light emitting and receiving section of the first assembly and the other light emitting and receiving section form a second area sensor assembly, and The area sensor of claim 1, wherein the second area sensor assembly forms an area sensor that covers the substantially rectangular area as a pair.